CAN TEMPORARY ARTERY CATHETERIZATION EXTEND LIMITS OF ISCHEMIA TIME FOR MACROREPLANTATION?

ABSTRACT We observe delayed referrals to appropriate Microsurgery Unit and definitive treatment of traumatic limb amputations. Cases with wrist proximal amputations have a deadline for surgical replantation as these configure life-threatening injuries. Objective: To analyze patients with traumatic proximal wrist upper limb amputations with prolonged ischemic time who underwent temporary artery catheterization to assess stump viability and results. Methods: A case-series study including all patients with a proximal wrist upper limb amputation and a cold ischemic time equal to or above six hours from 2017 to 2021. Results: In total, two surgeons operated eight patients who had experienced forearm amputation injuries. Median ischemia time totaled eight hours. All patients required additional surgeries, most commonly split-thickness skin graft or fixation revision (three patients). This study obtained five successful macroreimplantations. The mean cold ischemia time was longer in the group with successful macroreimplantations (7.4 hours) than of the unsuccessful group (9 hours). Conclusion: Macroreplantations require immediate referral to microsurgery and, although temporary artery catheterization helps surgical decision making, the technique seems to fail to influence outcomes. Level of Evidence IV, Retrospective Case Series.


INTRODUCTION
Upper limb macroreimplants with wrist proximal amputations represent life-threatening injuries that are associated with high-energy trauma.The decision to reimplant the amputated limb should be based on patients' clinical conditions and amputation stump techniques, according to injury type, amputation level, the conditions of stump soft tissues, and cold or warm ischemic time.
A recurrent problem in health systems refers to the prolonged time between the trauma of the limb and the moment in which the patient is received in the service that will perform such surgical procedure.This referral delay increases the chance of complications in patients undergoing macroreimplantation, such as microanastomosis thrombosis, muscle necrosis with rhabdomyolysis, infections, and others.Although some articles have recommended macroreimplantation up to 12 hours of cold ischemia, 1 Sabapathy et al. 2 consider that the critical time of cold ischemia would total eight hours, after which, the authors advise against macroreimplantation.Our referral service for complex orthopedics and traumatology cases often receives wrist proximal amputation cases late, forcing Brazilian microsurgeons to decide to try macroreimplantation in these dramatic cases in young patients.This study aims to critically analyze macroreimplants with prolonged ischemia times that received temporary artery catheterization to determine the viability of these amputation stumps and related clinical results., Chicago, IL, USA), was used for descriptive statistics and univariate analysis via the Student's t-test for quantitative data.In the descriptive analysis, intraoperative technical data (need for venous grafts, vessels used for arterial anastomosis, number of microanastomoses, venous system used for microanastomosis), total ischemic time, complications, and additional surgical procedures were evaluated.The selected cases were transferred to our service so patients could be evaluated.Limb macroreimplantation was indicated after the adequate stabilization of patients and preparation of the technical conditions for the procedure.The following sequence was set for surgical reimplantations: patients' admission to the hospital and clinical stabilization, preparation of blood and blood products, radiographs, and transport of the amputated part, correctly packed in a compartment with a saline solution and covered in ice to maintain its cold ischemia.The total cold ischemic time until the beginning of the surgical procedure was recorded and temporary artery catheterization with revascularization of the amputated part was performed.Regarding venous returns, the vein of the amputated part was freely bled for up to five minutes with adequate hemodynamic stabilization and consent of the anesthesiologist in the room.A Zeiss OPMI VARIO S88 microscope and 9.0 or 10.0 nylon suture threads (according to vessel diameter) were used.Prophylactic low-molecular-weight heparin (to prevent postoperative thrombosis in patients who underwent long surgeries), hydration, and analgesia were postoperatively performed at the beginning of recovery together with the intensive care team of the Hospital.

RESULTS
This study included eight wrist proximal amputations due to six work accidents, one automobile accident, and one train hit from 2017 to 2021.The first and third authors performed all surgeries in cases meeting our inclusion factors (Table 1).
Patients' age ranged from 23 to 37 years, averaging 29.4 years.Cold ischemic time ranged from six to 10 hours (standard deviation of 1.5 hours) with a mean of eight hours.The mean time of cold ischemia totaled 7.4 hours (standard deviation = 1.5 hours) for the group with successful macroreimplantations and nine hours (standard deviation = 1.0 hours) for the group with unsuccessful macroreimplantations (no statistically significant difference p = 0.12) (Figure 1).Cases showed the injury levels and associated injuries in Table 1.
The most common associated injury was extensive muscle injury (Figures 2 and 3).The team prepared stumps on a sterile operating table with adequate debridement, tendons, and nerves for repair (if feasible), and arteries and veins for microanastomoses.Each case underwent bone shortening and bone fixation preparation as needed (Figure 4).To reduce the time of additional intraoperative ischemia, all patients received artery catheterization with a silicone catheter before the steps to reimplant the amputated limb to quickly revascularize it.Patients also underwent free vein bleeding for five to 10 minutes to venously drain their stumps, as per the literature.3 The team adequately performed water support and volume replacement with blood and hydroelectrolytic products to replace volume due to increased bleeding stemming from temporary arterial catheterization.After revascularizing amputation stumps via temporary catheterization, this study analyzed patients' clinical stability and the viability of amputation stumps (by attesting to the absence of reperfusion ischemia, which could occur due to prolonged ischemia) and indicated macroreimplantation for the eight evaluated patients.After temporary artery catheterization, the team released muscle compartments, inspected the stumps, and debrided the segments without perfusion or bleeding by observing soft tissues (including the muscles) (Figure 5).Then, reimplantation followed the conventional steps in the literature.The surgical team performed fixation with plate and screws in five cases; with an external fixator in one case; and with Kirschner wires in one case (due to the absence of suitable material for urgent fixation).Moreover, one patient underwent wrist arthrodesis (Table 2).All patients required additional surgeries (Table 3) (Figure 6).Of the successful macroreimplantations, five patients reported using their limb functionally, remaining economically active, and working as administrative staff, porter, informal worker, or household worker (Figure 7).

DISCUSSION
Wrist proximal amputations are rare lesions that require specialized emergency support with clinical patient stabilization and a team specialized in microsurgical surgery.The study of macroreimplantation indications requires the assessment of patients' history and the characterization of lesions (trauma mechanism, level, elapsed time, and associated injuries) and comorbidities (peripheral arterial disease, diabetes, and smoking cause worse outcomes).In cases of segmental lesion, reimplantation should be rethought in the absence of clinical-hemodynamic stability and prolonged cold or warm ischemia.4 The adequate preservation of amputation stumps for macroreimplantation is essential for the best prognosis.Stumps should be wrapped with sterile gauze soaked in a physiological solution or immersed in a saline solution (plain water should be avoided) and placed in a closed compartment surrounded with ice to cool them to about 4°C.1,4 In Brazil, delays in patient and stump referrals raise the cooling temperature around the bag holding the stumps to above 4°C, which makes it impossible to determine the adequacy of stump cold ischemia in some cases.In other cases, although extensively described in the medical literature, amputation stumps are place directly on ice, leading to cooling burns and impairing case prognosis.An available resource in cases with prolonged cold ischemic time (over six to eight hours) is the temporary catheterization of the artery to rapidly revascularize the amputation stump.Nunley, Koman, and Urbaniak 5 described artery catheterization with or without vein catheterization for venous drainage in 1981, which can be used to evaluate amputation stump viability, especially that of ischemic muscles.However, temporary catheterization is neither a consensus nor should it delay arteriorrhaphies and final venorrhaphies.We recommend its use in cases with prolonged ischemia (over six to eight hours) and vein bleeding from five to 10 minutes with hemodynamic support to eliminate free radicals (including myoglobin, CPK, and potassium) and reduce the risk of acute renal failure or lethal consequences, as per the literature.3,5 Chin and Hart 6 described a case of traumatic wrist amputation, in which they used temporary artery catheterization due to the critical time of warm ischemia (above six hours), gaining time for adequate fixation and other repairs before definitive microanastomosis.In cases of wrist-proximal upper limb macroreimplantation, the classic sequence of finger reimplantation in the literature should be changed according to ischemic time and surgeons' preferences.The suggested order for macroreimplantation is: • Temporary shunt of the artery, according to prolonged ischemic time or surgeon's preferences (with the advantage of evaluating the viability of the muscle to be debrided) This surgical technique differs from distal reimplants due to the greater amount of muscle mass in proximal amputations, their greater susceptibility to necrosis due to ischemia, and the need for quicker revascularizations.Although digital amputations can withstand 12 hours of warm ischemia and 24 hours of cold ischemia, macroreimplants tolerate from two to three hours of warm ischemia and six to eight hours of cold ischemia, depending on their level.Unlike Sabapathy et al., 2 we recommend proximal myotendinous or muscular repair before the closure of soft tissues (rather than before the neurorrhaphy) as this muscle repair can aid covering noble structures, including nerves and repaired vessels since the skin for closing the macroreimplant may be compromised.With the advancement of techniques to prepare amputation stumps with target reinnervation of a muscle proximal to the amputation and techniques to sensitize cutaneous nerves with neurotization of the severed nerves of the stump (median, ulnar, and radial, according to availability and indication); the prognosis of patients without the possibility of reimplantation or with non-functional reimplanted limbs may improve with this evolution and new prostheses.7 However, studies describe even greater patient satisfaction and functional results, which may promote functional return and amputation stump sensitivity (including cases with unsatisfactory results), when compared to amputees and patients who received prostheses.8-10 In Brazil, GM/MS Ordinance 793 11 establishes the care network for people with physical disabilities within the Unified Health System and provides for upper limb prostheses 12 (including myoelectric devices following a multidisciplinary team's analysis according to the steps to prepare and grant orthoses, prostheses, or auxiliary means of locomotion as per the World Health Organization).13 However, the adherence of patients with upper limb amputations to the available upper limb prostheses remains low.Reasons for their dissatisfaction include poor prosthesis function, low comfort, high prosthesis weight, and inadequate adjustment.[14][15][16][17] Studies have shown 16,18 that patients who receive prosthetics soon after amputation, have more distal amputations, and receive adequate training, have greater long-term adherence to upper limb prosthesis.In our service, patients with traumatic wrist proximal amputations are often unable to undergo early prosthesis preparation following the WHO steps 13 and have low prosthesis use adherence.Moreover, patients' cultural preference for amputation usually configures a reimplantation attempt to the detriment of primary amputation.Studies have described that reimplanted patients suffer fewer psychological impacts, feel less disfigured, 19 and have better function (including return to work) and greater satisfaction than patients who received prostheses regardless of functional outcomes.15,20 Thus, our service prioritizes macroreimplantations whenever possible.The Hand Surgery 21 reference book indicates macroreimplantations for cold ischemic times ranging from six to 12 hours but states that from two to three hours of cold ischemia onward, amputation stumps begin to undergo muscle necrosis with risk of rhabdomyolysis and coagulopathy during macroreimplantation.On the other hand, Sabapathy et al. 22 recommend no reimplantations for the middle-third forearm after seven hours of cold ischemia and from the distal third of the arm to the middle third of the forearm after six hours.Most cases in our tertiary referral service for complex cases of orthopedic trauma show that the time elapsed between the trauma and the beginning of the surgical procedure exceeds six hours of cold ischemia, averaging eight hours in our casuistry.Although our comparison between the mean time of ischemia of successful and unsuccessful macroreimplantation cases showed no statistical differences, the mean of the successful group (7.4 hours) was lower than the group with macroreimplantation loss (mean of 9.0 hours).This absence of statistical difference may stem from the number of treated cases.However, due to the rarity of this severe lesion with ischemia times equal to or above six hours, this sample is comparable with the literature.23 We believe that the ischemic time limit for macroreimplants should consider the severity of the injury; anesthetic and clinical teams' technical and support conditions; and especially the adequate packaging of the amputated part, which arrives in inadequate preservation conditions in some cases.The limitation of this study refers to its number of cases as this is a serious and rare accident in Brazil, but its strength lies in its consecutive inclusion of all cases with prolonged ischemia time, being one of the largest national series.

CONCLUSION
Macroreimplants require immediate transport to specialized services.Moreover, temporary arterial catheterization to assist surgical management seems to fail to interfere with outcomes.

Figure 1 .
Figure 1.Case 6: (A, B) X-ray of the amputated limb on arrival at the hospital; (C) Radiography after three months of reimplantation showing no bone consolidation; (D) Image after eight years of surgery and a synthesis revision with good consolidation; (E) Clinical image of the limb after eight years.

Figure 3 .
Figure 3. Case 5: (A) Postoperative radiography with synthesis with plate and screws; (B, C) X-ray after nine years of surgery, showing bone healing; (D, E, F, G) Clinical images of the upper limb after nine years.

Figure 4 .
Figure 4. Case 2: (A, B, and C) Upper limb and amputated forearm; (D and E) Intraoperative images; (F and G) Appearance after one week of surgery; (H) Forearm X-ray after conversion for synthesis with a screw plate; (I) Aspect of the upper limb at follow-up.

Figure 5 .
Figure 5. Case 4: (A and B) X-rays of the wrist and amputated hand; (C) Appearance of the hand amputated by avulsion; (D) Debridement of non-viable tissue; (E and F) Final appearance after surgery; (G and H) Radioscopy imaging after wrist arthrodesis; (I) Image after skin graft surgery showing good integration; (J) Clinical image of the upper limb at follow-up; and (K) Patient holding an object.

Figure 6 .
Figure 6.Case 7: Clinical case with the longest cold ischemic time (10 hours).This female patient was hit by a train, which traumatically amputated her right forearm.The case evolved to worsened perfusion four days after macro-reimplantation and the patient chose amputation and regularization of her right upper limb.

Figure 7 .
Figure 7. Case 3: (A and B) Upper limb and amputated forearm; (C and D) Radiographs of the upper limb (showing an ipsilateral fracture of the humerus) and amputated forearm; (E) Intraoperative imaging with isolated vessels; (F) Final surgery image; (G) Postoperative X-ray with humerus, radius, and ulna synthesis; (H) Evolution with necrosis of the skin and of the soft portions of the anterior forearm; (I) post-surgery image of the anterolateral flap of the thigh for forearm coverage; (J) Final image of the upper limb; and (K) Evidence of function for activities of daily living.
project was submitted to the Research Ethics Committee under CAAE: 51739221.8.0000.0068.Informed consent forms were obtained from all patients following Resolution 466/12 of the National Research Ethics Commission.Individuals who were referred for surgical treatment of their traumatic upper limb injuries from 2017 to 2021 were included in this study.

Table 1 .
Descriptive epidemiological analysis of cases.

Table 2 .
Variables of the operative technique.

Table 3 .
Complications and additional surgeries.